US 2013/0315681 discloses a rotary cutting tool in the form of a twist drill, having an axis of rotation, a shank area and a cutting area. Disposed in the cutting area of the twist drill is a plurality of chip flutes which extend inwardly as far as a core profile. Throughout the length of the cutting area, there is a section in which the cross-sectional area of the core profile increases and a section in which the cross-sectional area of the core profile decreases. However, because of the drastically reduced cross-sectional area in the transition zone to the shank area, the stability of the twist drill both against lateral forces and against torsional forces is markedly reduced. As a result, vibrations are more likely to be generated, which have a negative effect on the service life and the machining quality.